Prius Prime Regeneration Braking Efficiency Experiment

Discussion in 'Prime Technical Discussion' started by erikrocketman1, Jun 1, 2018.

  1. erikrocketman1

    erikrocketman1 New Member

    Joined:
    Jun 1, 2018
    6
    14
    6
    Location:
    Los angeles
    Vehicle:
    2017 Prius Prime
    Model:
    Prime Premium
    I haven't seen any posts on regeneration efficiency, and wanted to do my own experiment. Pictures below.

    Bought a Prius Prime (Plug-in Hybrid w/ 6kW reserved for eV mode only) last week and naturally needed to nerd out with it!

    Took a vacation in Lake Arrowhead, California this Memorial day Weekend. Used this opportunity to calculate the regeneration efficiency of the Prius Prime by seeing how much energy it recharges to the batteries from the top of the mountain to the bottom.

    Using the elevation difference, and the total weight of the car with luggage and passengers, found that the regeneration efficiency to be about 51%, regenerating 3.22 kWh back to the battery from a 4400 ft altitude.

    Driving 110 miles the whole day and only used 0.65 gallons of gas! Car was at 100% battery at beginning of day, going down the mountain, I was at ~42% battery before descending the mountain, and managed to top of exactly at 100% at the bottom of the mountain). 169 mpg!

    Please share your stories!
     
  2. bisco

    bisco cookie crumbler

    Joined:
    May 11, 2005
    81,537
    35,245
    0
    Location:
    boston
    Vehicle:
    2012 Prius Plug-in
    Model:
    Plug-in Base
    welcome, beautiful!(y)
     
    erikrocketman1 likes this.
  3. PlugmeInplz

    PlugmeInplz New Member

    Joined:
    Jul 3, 2018
    22
    23
    0
    Location:
    LA
    Vehicle:
    2013 Prius Plug-in
    Model:
    Plug-in Base
    Its cool how you calculated this. What is interesting is the prime charged to 100% at the bottom of the hill, so the prime will not accept any more charge and brakes will absorb the excess energy. If you drained the battery at the top you could of potentially gotten an even larger charge increasing the regen efficiency. Great MPG
     
    erikrocketman1 likes this.
  4. PlugmeInplz

    PlugmeInplz New Member

    Joined:
    Jul 3, 2018
    22
    23
    0
    Location:
    LA
    Vehicle:
    2013 Prius Plug-in
    Model:
    Plug-in Base
    What was you EV to HV ratio?
     
    erikrocketman1 likes this.
  5. Roy2001

    Roy2001 Active Member

    Joined:
    Apr 1, 2009
    369
    151
    0
    Location:
    Sacramento, CA
    Vehicle:
    2017 Prius Prime
    Model:
    Prime Premium
    Great information!
     
    erikrocketman1 likes this.
  6. bisco

    bisco cookie crumbler

    Joined:
    May 11, 2005
    81,537
    35,245
    0
    Location:
    boston
    Vehicle:
    2012 Prius Plug-in
    Model:
    Plug-in Base
    stickied!(y)
     
    erikrocketman1 likes this.
  7. erikrocketman1

    erikrocketman1 New Member

    Joined:
    Jun 1, 2018
    6
    14
    6
    Location:
    Los angeles
    Vehicle:
    2017 Prius Prime
    Model:
    Prime Premium
    Actually, I got really lucky and hit 100% right before entering the freeway at the bottom of the hill, so no brake pad was used at all the whole way down!

    The entire 110 mile journey was about 69% EV driving ratio!
    HV mode didnt turn on until the last ~34 miles of my journey. Also, I didn't go into "B" mode down hill, for some reason it kicked on my engine.
     
    #7 erikrocketman1, Jul 19, 2018
    Last edited by a moderator: Jul 20, 2018
  8. Prime Objective

    Prime Objective New Member

    Joined:
    Jun 22, 2018
    4
    6
    0
    Location:
    Edmonton, Canada
    Vehicle:
    2018 Prius Prime
    Model:
    Upgrade
    If you do not want to use the ICE just switch back to "D" before stopping or accelerating.
    For an explanation of "B" mode Go to wiki books and search the following - Toyota Prius/Driving tricks
     
  9. axle2152

    axle2152 Active Member

    Joined:
    May 14, 2013
    260
    201
    0
    Location:
    North Carolina
    Vehicle:
    2018 Prius Prime
    Model:
    Prime Plus
    Nice to know that you can regenerate like that. One question is suppose you deplete the battery in EV and switch to HV and start going down a mountain where you can regenerate a lot, say 3kW or enough to be able to gain a good bit of EV range, would you be able to enter EV mode again? I think this was something the Volt cannot do (I watched a video of Volt owner shutting his car off to restart it to be able to use EV mode after regenerating down a mountain).
     
  10. CraigCSJ

    CraigCSJ Active Member

    Joined:
    Sep 2, 2004
    266
    136
    0
    Location:
    San Bernardino, CA
    Vehicle:
    2017 Prius Prime
    Model:
    Prime Advanced
    The answer for Prime is that after regenerating awhile the car showes between 1 and 2 miles of EV available and at that time EV driving is available. It may automatically switch to EV driving at that time.
     
  11. lili220

    lili220 New Member

    Joined:
    Dec 8, 2018
    1
    0
    0
    Location:
    alg
    Vehicle:
    2012 Prius c
    Model:
    ----USA----
    will absorb the excess energy. If you drained the battery at the top you could of potentially gotten an even larger charge increasing the regen efficiency. Great MPG
     
  12. JoyJonson

    JoyJonson New Member

    Joined:
    Dec 13, 2018
    2
    0
    0
    Location:
    Canada
    Vehicle:
    2012 Prius c
    Model:
    Five
    Thanks for info))

    I fount info what I needed

    I would like to know feedback about Toyta Camry LE;);)
     
    #12 JoyJonson, Dec 13, 2018
    Last edited by a moderator: Dec 13, 2018
  13. JoyJonson

    JoyJonson New Member

    Joined:
    Dec 13, 2018
    2
    0
    0
    Location:
    Canada
    Vehicle:
    2012 Prius c
    Model:
    Five
    :):):)сool
     
  14. montreal

    montreal Junior Member

    Joined:
    Dec 28, 2004
    4
    2
    0
    Excellent data. Thank you for posting it.

    It is worth keeping in mind that the calculations ignore parasitic losses. When ever a vehicle coasts (uphill, downhill or on level ground), it losses significant energy to aero drag and rolling resistance. That energy is gone and cannot be recaptured by regen.

    Actual wheels to battery efficiency is probably close to motor efficiency, so 70-80%?
     
Loading...